Caffeine side effects
may actually be good for us- break out the jumbo mug!

BY JEAN TANG, PHOTOGRAPHY BY FREDRIK BRODEN

Anything this good must be bad.

That's the prevailing attitude when it comes to caffeine, isn't it? We crave
it. We guzzle it. Drinking coffeemakes us
feel good — better able to handle an overbearing boss or an unruly pack of
toddlers. But then... we feel guilty about it, suspecting that sooner or later,
it's going to do us in.

In reality, it's not the guilty pleasure everyone makes it
out to be — in fact, caffeine side effects can do you good. So feel free to
grab a tall breakfast blend while we set the record straight.

Long-term caffeine consumption is just plain bad for me.

False.That myth exists in part because smokers, who metabolize
caffeine twice as fast as nonsmokers, drink more coffee drinks. And cigarette smokers have
more health problems. But nicotine, not caffeine, is the culprit. As long as
you don't have high blood pressure, heart arrhythmia, or anxiety, drinking
caffeinated beverages for years is no problem, says Harris Lieberman, Ph.D., a
research psychologist for the U.S. Army Research Institute of Environmental
Medicine.

Caffeine improves my game.

True.In terms of performance during your cardio workout, caffeine
"might be the difference between first place and last," Dr. Vinson
says. Without caffeine, not only are you a little slower mentally, you're
lagging physically. "Caffeine stimulates you to exercise 10 to 15 percent
longer" because it keeps you from getting as tired, explains Terry Graham,
Ph.D., a nutritionist who specializes in caffeine at Ontario's University of
Guelph. It's also a mild analgesic, so you can work out longer before you start
to feel sore. However, a troubling new study published in the Journal
of the American College of Cardiology shows that caffeine may decrease
blood flow to the heart during exercise. More research is needed.

Caffeine alters my body chemistry.

True.Caffeine is a natural stimulant, and 250 milligrams of it —
about the amount in two cups of strong coffee — will triple the amount of
adrenaline in your bloodstream, increasing your respiratory rate. In your
brain, caffeine intercepts adenosine, the chemical that slows down our nerves
and signals the need to sleep. It also increases dopamine levels, stimulating
pleasure centers. Caffeine, therefore, has the magical ability to make you feel
both alert and relaxed, says Ernesto Illy, Ph.D., an Italian biochemist and
founder of high-end coffee producer Illy Caffe.

Caffeine makes me smarter.

True. A cup of coffee before you write your performance review
isn't a bad idea. "It improves cognitive functions" by blocking that
brain-slowing adenosine, says Joe Vinson, Ph.D., a food chemist at the
University of Scranton. When given caffeine equal to two cups of coffee,
severely sleep-deprived Navy Seal trainees improved their alertness, vigilance,
learning, and memory by as much as 60 percent, according to Dr. Lieberman, who
administered the test.

Caffeine causes high blood pressure.

False.The Journal of the American Medical Association recently
reported that caffeine doesn't put you at risk for hypertension, although
something else, unknown to scientists, in sugared and diet colas does. In
people with normal blood pressure, any change in heart rate is not only
"too small to measure," Dr. Graham says, but it disappears within
minutes of your first cup. If you already have high blood pressure, however,
avoid excessive intake, says Lynne Shuster, M.D., director of the Mayo Clinic's
Women's Health Clinic, because caffeine can exacerbate a pre-existing
condition. The same goes for those who suffer from heart arrhythmia or anxiety
— caffeine can trigger arrhythmia in those who are prone to it and can worsen
anxiety.

Caffeine leads to bone loss.

False. There's evidence that calcium is lost through urine, and by
increasing the amount of urine you produce, you decrease your body's calcium
stores. The effect, however, is negligible. "A coffee drinker may lose a
few milligrams of calcium, but put one drop of milk in your coffee and you've
made up for the loss," says Jim Coughlin, Ph.D., a California-based food
toxicologist.

I can overdose on caffeine.

True.But most of the documented cases are of people who have
intentionally overdosed on high-powered caffeine pills (the lethal dose of
pills is about 50). To OD on caffeinated beverages, you would have to down
dozens of cups of coffee, hundreds of six-packs of soda, and thousands of mugs
of tea at the same time. The excess water would kill you before the caffeine
would, Dr. Illy says.

Caffeine is addictive.

True.You develop a tolerance to caffeine over time, and when you
no longer take any in, your body, expecting that daily dose, reacts with
headaches and irritability. The more caffeine you consume, the more severe the
withdrawal symptoms, but some people can get hooked on just a cup a day.
(Others can quit cold turkey, those lucky gals.)

If I have tea after dinner, I'll never fall asleep.

False.Tea has so little caffeine (25 milligrams per cup of weakly
brewed tea) that for most, it soothes rather than agitates. But beware of more
highly caffeinated drinks, especially if you're pregnant or on the Pill: It
takes 4 to 6 hours for an average adult to metabolize caffeine, no matter how
much you drink, and almost twice that long for a woman taking oral
contraceptives. (For a pregnant woman, this half-life shoots up to 18 hours.)
If you have trouble sleeping, stop drinking caffeinated beverages at least 6
hours before bedtime.

So, I can drink all the caffeine I want, with no consequences.

False.A Greek study suggested that moderate to heavy coffee intake
is associated with a higher level of inflammation. An immune system response,
inflammation can be harmful because too much of it can produce chemicals in the
body that have been linked to heart disease and diabetes. But just because
coffee was associated with inflammation doesn't necessarily mean it caused it.

Another recent study from the Harvard School of Public Health and the
University of Toronto finds that certain people, referred to as "slow
metabolizers," are genetically programmed to break down caffeine at a
slower rate. In the study, caffeine placed these people at increased risk for
heart attacks, while "rapid metabolizers" were protected against
heart attacks. Scientists believe that excess caffeine may lead to heart
disease but that other heart-healthy benefits from coffee, such as antioxidants,
outweigh the risk — as long as the caffeine doesn't linger in your system.
However, without a genetic test, it's impossible for the average Diet
Cokedrinking girl to determine which camp she falls into.

These researchers don't discourage caffeine consumption, but do warn against
caffeine in excess. A safe limit, according to the American Journal of
Clinical Nutrition, is around 400 milligrams — or four cups of coffee — a
day.